mehmet serhat Odabas

Publications (16) View all

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  Available from: mehmet serhat Odabas

  Article: Leaf area prediction for corn (Zea mays L.) cultivars with multiregression analysis

  F Oner, M S Odabas, I Sezer, F Odabas
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  ABSTRACT: Leaf area is one of the most important parameter for plant growth. Reliable equations were offered to predict leaf area for Zea mays L. cultivars. All equations produced for leaf area were derived as affected by leaf length and leaf width. As a result of ANOVA and multiregression analysis, it was found that there was a close relationship between actual and predicted growth parameters. The produced leaf-area prediction model in the present study is LA = a + b L + c W + d LZ where LA is leaf area, L is leaf length, W is maximum leaf width, LZ is leaf zone and a, b, c, d are coefficients. R 2 values were between 0.88–0.97 and standard errors were found to be significant at the p<0.001 significance level. Additional key words: leaf area; multiregression analysis; Zea mays L.
  Photosynthetica 01/2011; · 1.00 Impact Factor
• Article: Changes in the contents of main secondary metabolites in two Turkish Hypericum species during plant development.

  Cuneyt Cirak, Jolita Radusiene, Necdet Camas, Omer Caliskan, Mehmet Serhat Odabas
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  ABSTRACT: Context: The genus Hypericum (Guttiferae) has received considerable scientific interest as a source of biologically active compounds. Objective: The study determined the morphogenetic and ontogenetic variation in the main bioactive compounds of two Hypericum species, namely, Hypericum aviculariifolium subsp. depilatum var. depilatum (Freyn and Bornm.) Robson var. depilatum and Hypericum orientale L. through HPLC analyses of whole plants as well as individual plant parts (stems, leaves, and reproductive tissues). Materials and methods: The plant materials were harvested at five phenological stages: vegetative, floral budding, full flowering, fresh fruiting, and mature fruiting; dried at room temperature, then assayed for chemical content. Results: In H. aviculariifolium, no kaempferol accumulation was observed and the highest level of hypericin, pseudohypericin, and quercitrin was reached at full flowering (0.71, 1.78, and 4.15 mg/g DW, respectively). Plants, harvested at floral budding produced the highest amount of rutin, hyperoside, and isoquercitrine (32.96, 2.42, 1.52 mg/g DW, respectively). H. orientale did not produce hypericin, pseudohypericin, or kaempferol. Rutin, hyperoside, and isoquercetine levels were the highest at floral development (1.76, 11.85, and 1.21 mg/g DW, respectively) and plants harvested at fresh fruiting produced the highest amount of quercitrine and quercetine (0.20 and 1.30 mg/g DW, respectively). Discussion: For the first time, the chemical composition of the Turkish species of Hypericum was monitored during the course of ontogenesis to determine the ontogenetic and morphogenetic changes in chemical content. Conclusions: Plant material should be harvested during flower ontogenesis for medicinal purposes in which the content of many bioactive substances tested reached their highest level.
  Pharmaceutical Biology 03/2013; 51(3):391-9. · 0.88 Impact Factor
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  Article: Secondary metabolites of Hypericum orientale L. growing in Turkey: variation among populations and plant parts

  Acta Physiologiae Plantarum, Cuneyt Cirak, Jolita Radusiene, Zydrunas Stanius, Necdet Camas, Omer Caliskan, Mehmet, Serhat Odabas
  Acta Physiologiae Plantarum 01/2012; 34(34):1313-1320. · 1.64 Impact Factor
• Article: The quantitative effects of temperature and light intensity on phenolics accumulation in St. John's wort (Hypericum perforatum).

  Mehmet Serhat Odabas, Necdet Camas, Cuneyt Cirak, Jolita Radusiene, Valdimaras Janulis, Liudas Ivanauskas
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  ABSTRACT: The quantitative effects of temperature and light intensity on accumulation of phenolics were examined on greenhouse-grown plants of Hypericum perforatum L. Plants were grown in a greenhouse separated into two parts: shaded by 50% transparent polyethylene cover and un-shaded. Temperature values and light intensities were measured daily during the experiment, while plants were harvested weekly for HPLC analyses. Multi regression analyses were performed to describe the quantitative effects of temperature and light intensity on phenolics accumulation. According to the results, increases in temperatures from 24 degrees C to 32 degrees C and light intensities from 803.4 microMm(-2)s(-1) to 1618.6 microMm(-2)s(-1) resulted in a continuous increase in amentoflavone, apigenin-7-glucoside, cholorogenic acid, hyperoside, kaempferol, rutin, quercetin and quercitrin contents. The relationships between temperature, light intensity and phenolics accumulation were formulized as P= [a + (b1 x t) + (b2 x l) + [b3 x(t x l)]] equition, where P is the content of the corresponding phenolic, t temperature (degrees C), l light intensity (microMm(-2)s(-1)) and a, b1, b2 and b3 the coefficients of the produced equation. The regression coefficient (R2) value for amentoflavone was 0.84, for apigenin-7-glucoside 0.87, for cholorogenic acid 0.83, for hyperoside 0.95, for kaempferol 0.76, for rutin 0.70, for quercetin - 0.93, and for quercitrin - 0.86. All R2 values and standard errors of the equations were found to be significant at the p<0.001 level. The mathematical models produced in the present study could be applied by Hypericum researchers as useful tools for the prediction of phenolics content instead of routine chemical analyses.
  Natural product communications 04/2010; 5(4):535-40. · 1.24 Impact Factor
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  Article: Prediction Models for the Phenolic Contents in Some Hypericum Species from Turkey

  Serhat Mehmet, Odabas, Jolita Radušiene, Cüneyt Cirak, Necdet Camas
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  ABSTRACT: In this research, models for prediction of the content of several phenolics namely chlorogenic acid, hyperoside, apigenin-7-O-glucoside, rutin, quercitrin, quercetin and viteksin were developed for Hypericum originafolium Willd, Hypericum perfoliatum L. and Hypericum montbreii Spach. growing in Northern Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting, mature fruiting stages and dissected into stem, leaf and reproductive tissues. Actual phenolic content of plant materials was measured by high performance liquid chromato-graphy method. Multiple regression analysis with Excel 2003 computer package program was performed for each species and phenolic separately to develop the models. The produced equation for predicting of phenolic content in different tissues of the species was formulized as: PC= [a + (b1 × S) + (b2 × L) + (b3 × R) + (b4 × S 2) + (b5 × (1/RP))] where PC is whole plant content of phenolic compound, S is phenolic content of stem, L is phenolic content of leaf, RP is phenolic content of reproductive parts and a, b1, b2, b3, b4 and b5 are coefficients. R 2 values varied between 0.65-0.99 for H. originafolium, 0.67-0.99 for H. perfoliatum and 0.96-0.99 for H. montbreii depending of the phenolics examined. All R 2 values and standard errors were found to be significant at the p < 0.05 level.
  Asian Journal of Chemistry 01/2008; 20:4792-4802. · 0.27 Impact Factor